Military helicopters, combat vehicles and limousines could be made safer with an improved armor developed by researchers at ORNL. Tests at the lab show that tiles made of ORNL's boron carbide ceramic and facings made of polymer matrix composites provide superior armor-piercing bullet-stopping ability than commercially available ceramic armor. And, compared to steel, the ceramic material is two to three times harder, less than half the weight yet features greater stopping power. In tests performed at a ballistics range, the ceramic tiles sandwiched by four layers of a polymer matrix composite stopped 30-caliber armor-piercing bullets traveling up to 2,800 feet per second. "The hardness of the ceramic fractures the bullet, making it easier to stop small fragments," said Steve Nunn of the lab's Metals and Ceramics Division. If the project receives further funding, Nunn and colleagues plan to conduct tests to shed more light on why ORNL's tile provided for up to 24 percent better performance than commercially available ceramic tiles – and why ORNL's composite facing improved the ballistic performance of a commercial armor tile by 40 percent. [Contact: Ron Walli, 865-576-0226; wallira@ornl.gov]
SENSORS -- Super bomb sniffer . . .
A potentially inexpensive miniature sensor able to detect tiny amounts of airborne plastic explosives in just seconds could make it possible to safeguard virtually all airports and key public facilities in the United States. The ORNL micromechanical system (MEMS) has several advantages over conventional plastic explosives sensors, which are bulky and expensive. In comparison, ORNL's sensor consists of a 180-by-25-micron piece of silicon attached to a microcantilever and could be produced for a few dollars. One side of the microcantilever, which is like a tiny diving board, is coated with gold. The gold side is then coated with an acid (4-mercaptobenzoic) sensitive to PETN (pentaerythritol tetranitrate) and RDX (hexahydro-1,3,5-triazine). If these plastic explosives are present, the microcantilever moves and that motion is instantly detected by a laser-microscope that is part of the system. Developer Thomas Thundat of the lab's Life Sciences Division says the device can detect explosives at a level of 14 parts per trillion after just 20 seconds of operation. The work is to be published in the Aug. 18 issue of Applied Physics Letters. [Contact: Ron Walli, 865-576-0226; wallira@ornl.gov]
ENVIRONMENT -- Less sulfur, cleaner air . . .
Ridding natural gas of sulfur and other impurities means cleaner air, and it is the focus of a project that would take advantage of two technologies developed at ORNL. The goal is to build and demonstrate a low-cost regenerative desulfurizer based on the carbon fiber composite molecular sieve and electrical swing adsorption. Tim Burchell and colleagues first plan to refine and optimize the carbon fiber composite molecular sieve material's structure for adsorption of hydrogen sulfide and organic sulfides found in natural gas. Next, researchers in the lab's Metals and Ceramics Division will conduct dynamic adsorption experiments to evaluate and minimize the extent to which the sieve co-adsorbs other impurities in the gas stream. Provided adequate funding, the data from these experiments will be used to develop and construct a prototype scrubber to be tested by one or more of the Department of Energy's contractors. [Contact: Ron Walli, 865-576-0226; wallira@ornl.gov]
ENVIRONMENT -- Watching over a healthy stream . . .
Researchers at ORNL are joining with other agencies to monitor the health of a mountain river and possibly head off detrimental effects of upriver development. Little River, which flows out of the Great Smoky Mountains, is considered a relatively pristine stream despite growth of a resort area along its banks. This summer ORNL researchers have teamed with the Tennessee Valley Authority, Tennessee Wildlife Resources Agency and Tennessee Department of Environment and Conservation to briefly immobilize fish in the stream at a location below most of the new development. The ORNL researchers then assess the health of the fish. Over time, the fish will serve as an early-warning indicator on any stresses to their ecosystem, and measures may be taken in time to stem the damage. Also, Little River, because of its relatively clean state, is serving as a benchmark for other, more threatened or damaged streams. [Contact: Bill Cabage, 865-574-4399; cabagewh@ornl.gov]
PREPAREDNESS -- PASS passes DOE test . . .
Knowing whether people have safely evacuated a building during a drill or actual emergency can mean the difference between life and death, and it is the focus of a technology being developed at ORNL. While researchers envision the personnel accountability system being used for the Department of Energy, Gary Steimer of the lab's National Security Directorate sees many other potential applications. "In any federal or state building that houses hundreds of employees, our evacuation monitoring and accountability system would let responders and others know quickly who is still in a building," Steimer said. In fact, the United States government's National Imagery and Mapping Agency has asked ORNL to provide a proposed system for possible installation in one of its primary buildings. The project capitalizes on ORNL's expertise in computational sciences, electronics and radio frequency identification sensor technologies. Already, ORNL's Personnel Accountability Scanning System -– PASS -- has proven itself by meeting the DOE requirement to account for all personnel during an evacuation within 30 minutes or less, a requirement that previously could not be met. [Contact: Ron Walli, 865-576-0226; wallira@ornl.gov]
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